The invention relates to a lightweight, reinforced shear-resistant heddle frame slat for use in a heddle frame assembly on a loom. Typically, heddle frame slats are utilized in the construction of a heddle frame on a loom to support the heddle rods on the loom. The heddle frame includes a top frame slat and a bottom frame slat which are spaced apart in the frame by a pair of side frame members. The individual heddles are slideably carried on the heddle rods and supported in the frame. The heddles include eyes through which the warp ends are threaded. The heddle frame raises and lowers the warp ends to create an open space called a shed through which the weft yarn is inserted during weaving. In lifting the warp ends during shedding, the heddle frame undergoes forces in a vertical direction while moving the warp ends which produces a bending motion on the frame slat and also produces shear forces between the heddle rod and the frame slat.
As the speeds at which the looms are driven increases, the inertial loading on the heddle frames during shedding is greatly increased. Since the inertial forces are dependent upon the mass of the heddle frame assembly, there has been a great need to provide light-weight frames structures for the heddle frame assembly without sacrificing structural integrity. During shedding, the heddle frame assembly reciprocates vertically in fast rapid strokes which increase as the operating speed of the loom increases. Therefore, the provision of lightweight components for the heddle frame assembly is a problem to which considerable attention need be given.
Typically a number of heddle frame assemblies are used in juxtaposed position. Two heddle frame assemblies move in opposing directions to create the shed. The thickness of the heddle frame assembly affects the amount of spacing between the two heddles. The amount of spacing between the two heddle frames determines the amount that the heddle frame assembly must move vertically in order to create a shed having a desired height. The device which inserts the weft pick through the shed requires that the shed be of a certain height and size for clearance. As the distance between the heddle frame assemblies increases, the greater distance the heddle frames need to reciprocate vertically in order to create the shed. Therefore if the overall thickness of the heddle frame assembly can be reduced, the frames can be closer together with less vertical movement required to create a desired shed. With decreased vertical movement comes a decrease in inertial forces and loading caused by the shedding motion.
U.S. Pat. No. 4,484,604 commonly owned by the assignee of the present application discloses a composite dual-faced heddle frame slat which is lightweight, therefore rendering it desirable for use on a heddle frame assembly for purposes of reducing inertial loading. However, the problem arises that a considerable amount of shearing forces exists at the point of attachment of the heddle rod and the frame slat. This is a critical area of the heddle frame assembly since the heddles which support the warp ends are attached to the heddle rod. Shearing forces are exerted at the area of attachment of the heddle rod and frame slat due to the forces produced by the heddles on the heddle rods.
Accordingly, an important object of the present invention is to provide a frame slat for use in the heddle frame assembly of a loom which is lightweight and decreased in thickness to reduce inertial forces.
Still another important object of the invention is the provide a frame slat for a heddle frame assembly having an integral heddle rod with reduced shearing forces at the area of attachment.
Still another important object of the invention is to provide a frame slat for a heddle frame assembly which includes a uniquely formed mounting socket along the length of the heddle frame slat for attachment of the heddle rod with minimized shearing forces.
Still another important object of the invention is to provide a frame slat for a heddle rod assembly which can be fabricated from thin wall, roll-formed steel so that the frame slat is reduced in its overall thickness whereby the heddle frame assemblies can be placed closer together requiring less vertical movement during shedding.
Still another important object of the present invention is to provide a frame slat for a heddle frame assembly which may be fabricated from two thin roll-formed steel plates so that accessory and attachment blocks may be fabricated with the frame slat as well as the other reinforcing features in a simplified structure.